Chuck for gripping bars



p 6, 1949' I A. CAUCiHOIS 2,481,289

, CHUCK FOR GRIPPING BARS Filed March 3, 1948 hi Ca u, ch 0 z; 6

Patented Sept. 6, 1949 CHUCK FOR GRIPPING seas Andr Cauchois, Lille, France Application March 3, 1948, Serial No. 12,737

In France March 21, 1947 4 Claims. (01. 279-73) The present invention relates to a chuck for gripping bars, which is to be placed on a machine having a movement of rotation.

It is characterized by a double-coned ring formed with a neck on each side and with radial channels, in which there slide, parallel to their longitudinal axes, rollers of which one head part with spherical surface receives the thrust of two coned recesses of the same aperture, one fixed and the other guided by a number of keys, which approach one another under the action of a screwthreaded annulus or rod screwing into the central bore of the moving conically recessed ring, the rotation of this screw-threaded annulus or rod being produced by a set of coned gears which can be manipulated or operated by means of an external key, a ball-thrust being arranged between this threaded rod and the inner end of the chuck body.

It is further characterized by the arrangement along two diametrally opposite generatrices of each roller or half-channels closed at one end, in which are partially located cylindrical springs, the other part of which is located in corresponding half-channels closed at one end and formed in the ring accommodating the rollers.

Another characteristic consists in the feature that the double-coned ring maintaining the rollers comprises tenons which slide in guide slots formed in the body of the chuck and prevent this ring from turning.

As an alternative form, it is further characterized by the replacement of the spherical end of the rollers with a frusto-conical end.

The end of each of the rollers forming the jaw has two chamfered surfaces.

The accompanying drawings show diagrammatically by way of example one form of construction of the invention.

Figure 1 is a longitudinal axial cross section of the chuck.

Figure 2 is a front view, with a part in cross section, of the ring with its tightening or gripping rollers.

Figures 3, 4 and 5 are views of a gripping roller on a larger scale from above, from the side and from below respectively.

Figure 6 shows on the larger scale a side view of a tightening roller terminating in a frusto-conical part.

In Figure 1 can be seen at I the body of the chuck, the bottom or inner end of which is closed by a cast-on member 2, possessing a recess 3, coned or cylindrical, for fixing to the machine.

position bya screw-threaded ring 5. The cap 4 has on the inside a coned recess 6 of the same aperture as'the conical recess I of an annulus 8 sliding in the body ofthe chuck, the bore of which is internally: screw-threaded. Thus annulus 8, is guided longitudinally by one or more keys 9,

which are solidly connected therewith and slide in slots IEI formed in the internal bore of the chuck.

Between theconed recesses 6 of the cap and I of the annulus 8 are pressed the heads of rollers I I. These rollers are located in channels formed radially in a double coned ring I3 comprising cylindrical neck parts IZand I2 and having pins I4. which can slide in the slots I0, serving to guide the keys 9 of the annulus 8.

Into the internal screw-threaded bore of the annulus 3 is screwed a member I5, provided with a flange I6, the edges of which are cut as a bevel gear I'I, so as to form a bevel pair with a gear I8, which is rigid with a key I9, the end 20 of which can pivot in a cavity formed in the bottom 2 of the chuck.

The flange I6 of the part I5 is maintained at the side of the head of the chuck by means of a resilient ring or guard ring 2|.

Between the inner end of the part I5 and the inner end of the bottom 2 of the chuck is arranged a ball thrust bearing 22.

Each roller II has two diametrically opposite: lateral slots 23 and 24, closed at one end, corre-- sponding to two similar slots 25 and 26 formed in. the ring I3. These two slots register with one:

another and form locations for cylindrical springs: 21, one end of each of which bears on the roller and the other end on the ring. The purpose of. these springs is to separate the rollers when the chuck is slackened, and they form at the same time guides and keys to prevent the rollers from turning in their location.

As shown in the drawings, the base of the roller forming a jaw possesses two chamfers 28 and 29, having between them a plane part 30 forming the gripping surface, which may with advantage be knurled as shown in Figure 5.

As shown in Figure 6, the head of the roller may have a conical surface instead of a spherical surface.

The chuck formed according to the invention has the following advantages:

Great gripping power without overhang of the jaws; rigorous precision in consequence of the ease of machining of the parts; large gripping surface of the jaws; reduced overall dimensions This chuck body is closed by a cap II, held in for a large gripping power.

I claim:

1. A roller chuck for gripping bars, comprising: a chuck body formed with a frusto-conical recess at its inner end, an annulus longitudinally slidable and guided in the chuck body, the annulus being formed with a frusto-conical recess facing and co-axial with that of the chuck body, a ring located between and co-axial with the said t qni ak rea ss h e gs in formed withradiah guiding apertures and also with two externally frusto-conical surfaces facing the frusto-conical recesses, neck portionsprojecting axially from the said ring one o-,the said neck portions being guided in the sliding annulus, and the chuck body being formed with 15:

a longitudinal aperture for guiding the; other neck portion, rollers radially slidable in the aper tures in the ring, bevelled surfaces at the outer ends of the rollers engaging with the frust-o-- conical surfaces of the recesses, and actuating means operable from ioutside;.theschuekgbodmfora shifting; the sliding annulus longitudinally.- ands therebyiforcing the rollers radially:- inwards;-v

2. A; rollert-ehuck. fontgrippingybars comprise 4 longitudinal aperture for guiding the other neck portion, rollers radially slidable in the apertures in the ring, bevelled surfaces at the outer ends of the rollers engaging with the frusto-conical 5 surfaces of the recesses, an internal screw thread in the annulus, an externally screw-threaded member meshing with the said thread, bevel gear teeth on the externally threaded member, a bevel pinion.;,journalled inthe ChlfiClQsab'QdYg and' meshing with the-said gear-teeth, and actuating means operable from outside the chuck body for rotating -the said pinion, thus shifting the sliding annulus, longitudinally and thereby forcing the rollers radially inwards.

331 ALrollen chuck for gripping :bars as claimed in, claim 2,, further comprising a ball-thrust bearing -interposed"between the externally screwthreaded member and the chuck body.

4:: Ahroller chuck for gripping bars as claimed in claim 1, further comprising tenons projectfrom-th sdo bl r. on d:rinefih iticarri eth llers, hee huckodm in iformed.z ithi oneietudin l guiding oves inrwhic. thelsaid .tenonszl n a o; as. to p v nt the saidwrin from ing: a chuck body formedwitmatfrustoeceniealee recess-at its-inner end, an annuluslongitudmallye slidable -andguided ln the-chuck body;-- theam l nulus being formed Witlra frusto-oon-ical recesa facing-'and co-axial with that of themhuok body,

ANDREECAUGHQISK F EN E G T-ED 1 The following referencesare of 'recordin the a ring 7 located -between-- and -co-axial with; the Wei-11 i Qfthis; patent;

said frusto-conicab recesses, the ring being formed with; radial 5 guiding; apertures ands also: with two; externally frusto-conioalsurtaces fae ing-the frusto-conicahrecesses, neck-portions pjecting axially from the said-iring;'one ofs-said fir neck portions beingguided in the sliding ansnulus, and the chuck bodybeing -fermed?ivi'thaaav UNITED e Es -ATENTa Number Name Date" 171';-160 Moul-ton Dec; 14; 1875* 310,308 Moore Jan; 6; 1885* 3135472 Ghappell M ar; 10,"1885- 

